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perf events: Separate the routines handling the PERF_SAMPLE_ identity…
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… fields

Those will be made available in sample like events like MMAP, EXEC, etc in a
followup patch. So precalculate the extra id header space and have a separate
routine to fill them up.

V2: Thomas noticed that the id header needs to be precalculated at
inherit_events too:

LKML-Reference: <alpine.LFD.2.00.1012031245220.2653@localhost6.localdomain6>

Tested-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ian Munsie <imunsie@au1.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1291318772-30880-2-git-send-email-acme@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Arnaldo Carvalho de Melo committed Dec 5, 2010
1 parent 614b678 commit 6844c09
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Showing 2 changed files with 76 additions and 54 deletions.
1 change: 1 addition & 0 deletions include/linux/perf_event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -759,6 +759,7 @@ struct perf_event {

struct perf_event_attr attr;
u16 header_size;
u16 id_header_size;
u16 read_size;
struct hw_perf_event hw;

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129 changes: 75 additions & 54 deletions kernel/perf_event.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,28 @@ static void unclone_ctx(struct perf_event_context *ctx)
}
}

static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;

return task_tgid_nr_ns(p, event->ns);
}

static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;

return task_pid_nr_ns(p, event->ns);
}

/*
* If we inherit events we want to return the parent event id
* to userspace.
Expand Down Expand Up @@ -351,15 +373,30 @@ static void perf_event__header_size(struct perf_event *event)
if (sample_type & PERF_SAMPLE_IP)
size += sizeof(data->ip);

if (sample_type & PERF_SAMPLE_ADDR)
size += sizeof(data->addr);

if (sample_type & PERF_SAMPLE_PERIOD)
size += sizeof(data->period);

if (sample_type & PERF_SAMPLE_READ)
size += event->read_size;

event->header_size = size;
}

static void perf_event__id_header_size(struct perf_event *event)
{
struct perf_sample_data *data;
u64 sample_type = event->attr.sample_type;
u16 size = 0;

if (sample_type & PERF_SAMPLE_TID)
size += sizeof(data->tid_entry);

if (sample_type & PERF_SAMPLE_TIME)
size += sizeof(data->time);

if (sample_type & PERF_SAMPLE_ADDR)
size += sizeof(data->addr);

if (sample_type & PERF_SAMPLE_ID)
size += sizeof(data->id);

Expand All @@ -369,13 +406,7 @@ static void perf_event__header_size(struct perf_event *event)
if (sample_type & PERF_SAMPLE_CPU)
size += sizeof(data->cpu_entry);

if (sample_type & PERF_SAMPLE_PERIOD)
size += sizeof(data->period);

if (sample_type & PERF_SAMPLE_READ)
size += event->read_size;

event->header_size = size;
event->id_header_size = size;
}

static void perf_group_attach(struct perf_event *event)
Expand Down Expand Up @@ -3357,6 +3388,36 @@ __always_inline void perf_output_copy(struct perf_output_handle *handle,
} while (len);
}

static void perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
{
u64 sample_type = event->attr.sample_type;

data->type = sample_type;
header->size += event->id_header_size;

if (sample_type & PERF_SAMPLE_TID) {
/* namespace issues */
data->tid_entry.pid = perf_event_pid(event, current);
data->tid_entry.tid = perf_event_tid(event, current);
}

if (sample_type & PERF_SAMPLE_TIME)
data->time = perf_clock();

if (sample_type & PERF_SAMPLE_ID)
data->id = primary_event_id(event);

if (sample_type & PERF_SAMPLE_STREAM_ID)
data->stream_id = event->id;

if (sample_type & PERF_SAMPLE_CPU) {
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
}
}

int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size,
int nmi, int sample)
Expand Down Expand Up @@ -3459,28 +3520,6 @@ void perf_output_end(struct perf_output_handle *handle)
rcu_read_unlock();
}

static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;

return task_tgid_nr_ns(p, event->ns);
}

static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;

return task_pid_nr_ns(p, event->ns);
}

static void perf_output_read_one(struct perf_output_handle *handle,
struct perf_event *event,
u64 enabled, u64 running)
Expand Down Expand Up @@ -3655,37 +3694,17 @@ void perf_prepare_sample(struct perf_event_header *header,
{
u64 sample_type = event->attr.sample_type;

data->type = sample_type;

header->type = PERF_RECORD_SAMPLE;
header->size = sizeof(*header) + event->header_size;

header->misc = 0;
header->misc |= perf_misc_flags(regs);

perf_event_header__init_id(header, data, event);

if (sample_type & PERF_SAMPLE_IP)
data->ip = perf_instruction_pointer(regs);

if (sample_type & PERF_SAMPLE_TID) {
/* namespace issues */
data->tid_entry.pid = perf_event_pid(event, current);
data->tid_entry.tid = perf_event_tid(event, current);
}

if (sample_type & PERF_SAMPLE_TIME)
data->time = perf_clock();

if (sample_type & PERF_SAMPLE_ID)
data->id = primary_event_id(event);

if (sample_type & PERF_SAMPLE_STREAM_ID)
data->stream_id = event->id;

if (sample_type & PERF_SAMPLE_CPU) {
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
}

if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;

Expand Down Expand Up @@ -5745,6 +5764,7 @@ SYSCALL_DEFINE5(perf_event_open,
* Precalculate sample_data sizes
*/
perf_event__header_size(event);
perf_event__id_header_size(event);

/*
* Drop the reference on the group_event after placing the
Expand Down Expand Up @@ -6102,6 +6122,7 @@ inherit_event(struct perf_event *parent_event,
* Precalculate sample_data sizes
*/
perf_event__header_size(child_event);
perf_event__id_header_size(child_event);

/*
* Link it up in the child's context:
Expand Down

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